Despite intensive efforts, the aetiology of Osteoarthritis (OA) remains elusive, however, genetic factors have been found to be strong determinants of the disease. Recent studies in Dr. Moreau’s lab have demonstrated an aberrant nuclear accumulation of PHB-1, a ubiquitous protein implicated in multiple cellular processes, in human OA articular chondrocytes. Moreover, we have shown that PHB-1 is part of a repressor complex that binds to the promoter of Pitx1 transcription factor, through the recognition of an E2F-like binding site which could contribute to OA onset. The role of Pitx1 and PHB-1 in OA pathogenesis is not clear, the goal of this study was to characterize PHB-1 nuclear accumulation in OA chondrocytes and to determine the molecular mechanisms by which PHB-1 accumulates in the nucleus of OA chondrocytes. In our studies we used U2Os and C28/I2 as well as human chondrocytes obtained from OA and control patients. Our data confirmed that PHB-1 accumulates in the nucleus of about 55 percent of OA patients and that this accumulation correlates with an increased in sumoylation of the proteins in the nuclear fraction of OA chondrocytes. Present findings suggest that increased sumoylation could trigger PHB-1 nuclear accumulation through binding of PHB-1 to a sumoylated protein via a SUMO interacting motif (SBM) mapped to residus 76 to 79 of PHB-1. Moreover, these results demonstrate that sumoylated proteins accumulate in PML nuclear bodies in the nucleus of OA chondrocytes, suggesting the recruitment of SUMO-interacting proteins in PML bodies of arthritic chondrocytes. Further studies are needed to identify the potential sumoylated proteins which are interacting with PHB1.